New to this

I'm completely new to this sort of thing but a few days ago I had a strange experinece and I was hoping someone could help me figure out if my house is haunted and how to make it stop. 3 nights ago I left my phone that had died on my couch and I went and took a nap. I woke up later and I was going to leave. I was going to charge my phone while I was gone so I went to the living room to grab it and it was gone. I have 3 cats and I assumed one of them could have pushed it off the couch. I looked under, in, around my couch for 25 minutes to no avail. Since it was dead it wasn't a matter of just calling it so I looked every where. An hour and 45 minutes later I gave up. The next day while I was changing the sheets on my bed I lifted up the mattress to find my phone. I would generally blame such happenings on my cats but I'm pretty sure my 6lb cat couldn't life the matress up and place my phone there. I'm a extremely weirded out by this. Help please!

Yeah. After this last one happened it made me start rethinking those moments where I would find something some where I swore I hadn't left it. Two times in particular stick out. I always take my shoes off by the door when I get home. I found one of them by the door where I left it and one again in my bedroom. Also my keys come up missing pretty frequently. I always just assumed my cats were behind it or maybe my fiance had something to do with it.....

I have this all the time where I'm living at the moment.
I understand that when you aren't used to it the experiences can make you feel uncomfortable but I doubt you have anything to worry about.
For me it's just become one of the parts of everyday life, I've noticed when it happens to me when I'm getting annoyed I always end up muttering to myself things like "Come on I need ____ back now" or "Give _____ back please it's annoying" and that generally makes the search a lot shorter.
When I do this the things always pop up in more obvious places too so it helped me because it stopped me from thinking I was losing my mind since it was always in a place I'd definitley checked beforehand.

Yeah that's one of a ghosts favorite trick. Best thing to do is keep your important stuff on you at all times, never set anything like keys or phones down. Leave them attached to you, or in your pockets. There isn't much else you can do to stop them outright. They are just trying to get your attention, so talking to them and letting them know you are aware of them might help a lot. Ghosts get mad at us because they think we are ignoring them, and then they act out and play kiddy games like this with us. Treat them like a real person living with you, come in and say hi once and a while as long as they are not doing anything nasty or harmful there is no reason to get upset at having a playful ghost around.